David H. Petraeus, former army general and head of the Central Intelligence Agency, tastes a ceremonial cake presented to him by Hector Sandoval, a member of the USC ROTC program, at Tuesday's annual dinner for veterans and ROTC students at the Univeristy of Southern California, in downtown Los Angeles. (ASSOCIATED PRESS / Reed Saxon)

LOS ANGELES (AP) — In his first public speech since resigning as head of the CIA, David Petraeus apologized for the extramarital affair that “caused such pain for my family, friends and supporters.”

The hero of the Iraq and Afghanistan wars struck a somber, apologetic tone as he spoke to about 600 people, including his wife and many uniformed and decorated veterans, at the University of Southern California’s annual ROTC dinner on Tuesday.

“I know I can never fully assuage the pain that I inflicted on those closest to me and a number of others,” Petraeus said.

Petraeus has remained largely in seclusion since resigning after the extramarital affair with his biographer was disclosed. His lawyer, Robert B. Barnett, has said Petraeus spent much of that time with his family.

Dressed in a dark suit and red tie, Petraeus made motions toward a return to public life as a civilian. He spoke of a need for better treatment for veterans and soldiers, though he stopped short of criticizing current practices.

“While our country continues to improve its support and recognition for all of our veterans and their families, we can and must do more,” he said.

The retired four-star general also noted the challenges of transitioning from military life, saying: “There’s often a view that because an individual was a great soldier, he or she will naturally do well in civilian world. In reality, the transition from military service to civilian pursuits is often quite challenging.”

He received applause and a standing ovation before he began the evening’s program by cutting a cake with a sword in military tradition, a task reserved for the highest ranking person in the room.

He started his speech by addressing the affair with biographer Paula Broadwell, which was discovered during an FBI investigation into emails she sent to another woman she viewed as a romantic rival.

“Needless to say, I join you keenly aware that I am regarded in a different light now than I was a year ago. I am also keenly aware that the reason for my recent journey was my own doing. So please allow me to begin my remarks this evening by reiterating how deeply I regret — and apologize for — the circumstances that led to my resignation from the CIA and caused such pain for my family, friends and supporters,” he said.

At the time the affair was made public, Petraeus told his staff he was guilty of “extremely poor judgment” and that the “such behavior is unacceptable, both as a husband and as the leader of an organization such as ours.”

As the military leader credited with reshaping the nation’s counterinsurgency strategy, turning the tide in the U.S. favor in both Iraq and Afghanistan and making the U.S. safer from terrorism, a friendly audience was expected at the ROTC dinner.

At least one expert in crisis communications said that if his apology comes across as heartfelt and sincere, the public will indeed be seeing much more of him.

“America is a very forgiving nation,” said Michael Levine who, among dozens of other celebrity clients, represented Michael Jackson during his first child molestation investigation.

“If he follows the path of humility, personal responsibility and contrition, I submit to you that he will be very successful in his ability to rehabilitate his image,” he said.

Another longtime crisis communications expert, Howard Bragman, said Petraeus has handled the situation perfectly so far. He noted that unlike former President Bill Clinton, former U.S. Sen. John Edwards and other public figures caught in extramarital affairs, Petraeus didn’t try to lie his way out of it, immediately took responsibility and moved on.

“I think the world is open to him now,” said Bragman, vice chairman of the image-building company Reputation.com. “I think he can do whatever he wants. Realistically, he can even run for public office, although I don’t think he’d want to because he can make more money privately.”

While at USC, Petraeus also planned to visit faculty and students at the Price School of Public Policy, which administers the ROTC program, and USC’s School of Social Work, which trains social workers in how to best help veterans returning from war.

Petraeus was presented with a gift of silver cuff links by Nikias after his speech.